Dave wrote:

I am unclear on the use of the term "feedpoint" to describe the exposed
center conductor of the coax. Can you give me a little more detail as to
what this means? Sorry, I just don't understand why it is called the
feedpoint. I somehow thought that was where the coax connecting the antenna
to the receiver/transmitter was attached. And just for the record, I am
only going to be receiving with whatever type of loop I end up with. What
I am actually seeking is a small loop that I can attach to my tunable RF
amplifier for feeding enhanced signal to my Sony 7600GR shortwave radio,
making a portable unit to pair with the radio, allowing me to set them both
up wherever I wish. . .

I might be able to shed a little more light on this.

If you directly feed an unshielded loop, you cut a gap in the loop and
connect a transmission line across it. Current induced in the loop by a
signal flows from the loop to the transmission line via this connection.

In a "shielded" loop, the signal induces a current on the outside of the
"shield". At the gap, the current flows to the inside of the "shield"
where it induces an equal and opposite current into the inner loop
itself. The inside of the "shield" and the inner loop comprise an
ordinary non-radiating coaxial transmission line, so it can be said that
the gap is where the signal-induced current enters the transmission
line, just like the gap in the unshielded loop. And so the gap in the
"shielded" loop is a feedpoint in exactly the same sense as the gap in
an unshielded loop.

Roy Lewallen, W7EL